How to avoid AES key disclosure while doing encryption in client side and decryption in server side?

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C#

ASP.NET

Javascript

AES

I want to avoid AES Key disclosure while doing encryption in client side and decryption in server side. I am doing the encryption via javascript and decryption in the server side during login process. I am using aes js file for the same. Functionality is working fine But I am facing AES Key (7061737323313233) value as a vulnerability issue. i tried several ways like fetching from Config and passing to a js file etc. But still the vulnerability is there.
I need a resolution for this or alternate encryption decryption mechanism (Encryption at client level and decryption at server level)

What I have tried:

My javascript to do encryption is as below:

function EncryptAES() {
    var clearpass = document.getElementById('txtPassword').value;
    var key = CryptoJS.enc.Utf8.parse('7061737323313233');
    var iv = CryptoJS.enc.Utf8.parse('7061737323313233);
    var encrypted = CryptoJS.AES.encrypt(CryptoJS.enc.Utf8.parse(clearpass), key,
        {
            keySize: 128 / 8,
            iv: iv,
            mode: CryptoJS.mode.CBC,
            padding: CryptoJS.pad.Pkcs7
        });
  
    document.getElementById('txtPassword').value = encrypted;
}